Porous membranes are used in various fields such as the water treatment field including drinking water production, water purification treatment, and wastewater treatment. In recent years, simplification of the manufacturing process has been desired in addition to the performance of membrane such as high fractionation performance or hydrophilicity.
As the production method for obtaining a porous membrane, for example, as in Patent Document 1, a production method including a step of containing a hydrophilic macromolecule such as polyvinylpyrrolidone (PVP) as a pore forming agent in a polymer which forms a membrane substrate, producing a membrane, and then removing the hydrophilic macromolecule is mentioned.
In addition, a separation membrane containing a hydrophilic macromolecule, such as a graft copolymer or random copolymer of vinylpyrrolidone and a (meth)acrylate, that is treated to be insoluble in water so that the hydrophilic component does not elute into water for the purpose of hydrophilizing the porous membrane is disclosed in Patent Document 2 and Patent Document 3.